营养强化馒头加工和贮藏中叶黄素的稳定性研究

Stability of Lutein in Fortified Steamed Bread during Processing and Storage

为了研究叶黄素在强化馒头制作和储藏过程中的稳定性,将叶黄素水溶性微囊粉添加至馒头中,测定叶黄素及其异构体在馒头和面、压延、发酵、蒸制和储藏过程中变化情况。结果表明:和面、压延、发酵对叶黄素的降解影响不大,蒸制引起馒头中叶黄素含量略有下降,每份馒头中仍含有66.60%的全反式叶黄素。叶黄素强化馒头整个制作和储藏过程都伴随着顺式异构体的生成,和面过程中生成少量的13-顺式和13'-顺式叶黄素,压延过程中13-顺式和13'-顺式叶黄素含量继续增加,发酵过程生成少量的9-顺式和9'-顺式叶黄素,发酵和蒸制均引起13-顺式、13'-顺式、9-顺式和9'-顺式叶黄素含量的显著增加。整个储藏期间馒头中全反式叶黄素及顺式异构体含量略有下降,温度越高,叶黄素降解越快,-18℃冻藏更利于叶黄素强化馒头的保藏。

Water-soluble,microencapsulated lutein powder was added to steamed bread and the changes in stability of lutein and its stereoisomers was monitored during the processes of mixing,rolling,fermentation,steaming,and storage.The results showed that the concentration of lutein was not significantly affected during mixing,rolling,and fermentation;however,steaming caused a slight decrease in lutein concentration.The steamed bread contained 66.60% trans-lutein and cis-isomers were found during all stages of processing and storage of fortified bread.Small amounts of 13-cis and 13′-cis-lutein were generated during mixing and their levels continuously increased during the rolling process.Small amounts of 9-cis and 9′-cis-lutein were formed during fermentation,whereas both,fermentation,and steaming caused significant increases in the amounts of 13-cis,13＇′-cis,9-cis and 9′-cis-lutein.The content of trans-lutein and cis-isomers of lutein decreased slightly during storage.Degradation of lutein accelerated with increase in temperature and the optimum storage temperature for fortified steamed bread was at-18 ℃.